If a signal is pending we might return -ENOMEM instead of -EINTR.
We should propagate the proper error during KSM unsharing.
unmerge_ksm_pages returns -ERESTARTSYS on signal_pending. This gets
translated by entry.S to -EINTR. It is important to get this error
code so that userspace can retry.
To make this clearer we also add -EINTR to the documentation of the
PV_ENABLE call, which calls unmerge_ksm_pages.
Fixes: 3ac8e38015d4 ("s390/mm: disable KSM for storage key enabled pages")
Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
Reported-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
Tested-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
Documentation/virt/kvm/api.rst | 6 ++++++
arch/s390/mm/gmap.c | 9 +++++----
2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index bae90f3cd11d..2edb28bd07a9 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -4677,6 +4677,12 @@ KVM_PV_ENABLE
command has succeeded, any CPU added via hotplug will become
protected during its creation as well.
+ Errors:
+
+ ===== =============================
+ EINTR an unmasked signal is pending
+ ===== =============================
+
KVM_PV_DISABLE
Deregister the VM from the Ultravisor and reclaim the memory that
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 03c899849c38..2fbece47ef6f 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2552,12 +2552,13 @@ int gmap_mark_unmergeable(void)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
+ int ret;
for (vma = mm->mmap; vma; vma = vma->vm_next) {
- if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
- MADV_UNMERGEABLE, &vma->vm_flags)) {
- return -ENOMEM;
- }
+ ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
+ MADV_UNMERGEABLE, &vma->vm_flags);
+ if (ret)
+ return ret;
}
mm->def_flags &= ~VM_MERGEABLE;
return 0;
--
2.25.1
